Incidence of pulmonary embolism in deep venous thrombosis.

Abnormal radionuclide phlebograms were found in 65 patients in whom simultaneous-perfusion lung scintigrams and phlebograms were performed. All these patients were on adequate treatment with heparin for deep venous thrombosis. In 28% of the cases, the diagnosis of pulmonary embolism was made because they had abnormal perfusion lung scans with normal chest radiograph and clinical symptoms of pulmonary embolism.